diff --git a/src/Protocol/ActivityPub/Processor.php b/src/Protocol/ActivityPub/Processor.php
index 03c68eac00..b896dfa147 100644
--- a/src/Protocol/ActivityPub/Processor.php
+++ b/src/Protocol/ActivityPub/Processor.php
@@ -281,6 +281,11 @@ class Processor
 		}
 
 		if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
+			if (Queue::hasWorker($activity)) {
+				Logger::notice('There is already a worker task to dfetch the post.', ['parent' => $activity['reply-to-id']]);
+				return [];
+			}
+
 			$recursion_depth = $activity['recursion-depth'] ?? 0;
 			Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 			if ($recursion_depth < 10) {
diff --git a/src/Protocol/ActivityPub/Queue.php b/src/Protocol/ActivityPub/Queue.php
index f8f5666d13..d5a308b109 100644
--- a/src/Protocol/ActivityPub/Queue.php
+++ b/src/Protocol/ActivityPub/Queue.php
@@ -104,6 +104,20 @@ class Queue
 		DBA::update('inbox-entry', ['wid' => $wid], ['id' => $activity['entry-id']]);
 	}
 
+	/**
+	 * Check if there is an assigned worker task
+	 *
+	 * @param array $activity
+	 * @return bool
+	 */
+	public static function hasWorker(array $activity = []): bool
+	{
+		if (empty($activity['worker-id'])) {
+			return false;
+		}
+		return DBA::exists('workerqueue', ['id' => $activity['worker-id'], 'done' => false]);
+	}
+
 	/**
 	 * Process the activity with the given id
 	 *
@@ -123,7 +137,8 @@ class Queue
 		$type     = $entry['type'];
 		$push     = $entry['push'];
 
-		$activity['entry-id'] = $entry['id'];
+		$activity['entry-id']  = $entry['id'];
+		$activity['worker-id'] = $entry['wid'];
 
 		if (!Receiver::routeActivities($activity, $type, $push)) {
 			self::remove($activity);
@@ -150,7 +165,7 @@ class Queue
 	 */
 	public static function clear()
 	{
-		DBA::delete('inbox-entry', ["`received` < ?", DateTimeFormat::utc('now - 2 days')]);
+		DBA::delete('inbox-entry', ["`wid` IS NULL AND `received` < ?", DateTimeFormat::utc('now - 4 hours')]);
 	}
 
 	/**